This invention relates to cleaning applications that require low foam or non-foam cleaning formulations such as in automatic dishwashers, Cleaning in Place (CIP), automatic floor scrubbers, enclosed parts cleaning and the like. Any foam that is generated in these systems should be unstable and break down rapidly to prevent accumulation of foam during the process.
Typical hard surface cleaning formulations consist of a nonionic surfactant or solvent component, an electrolyte component (chelates or builders) and a hydrotropic co-surfactant (amphoteric, anionic or cationic surfactants). Quaternary ammonium compounds can function as the hydrotropic co-surfactants.
In the cleaning industry there are several specialized categories of cleaning where foaming can be very detrimental to the application. Examples of such formulations include Cleaning In Place formulations, automatic floor scrubber formulations, automatic dishwasher formulations, re-circulatory metal parts cleaning and the like. These types of formulations demand low, fast breaking foams to avoid overflow, product loss, pump cavitation, and streaks/films on treated surfaces after drying. If the cleaning formulation shows any tendency to foam then the high turbulence caused by either brushes or water sprays will result in foam.
In order to address the foaming issues, formulators often add oils or silicon defoamers to reduce or eliminate foam. Often these additives leave films and deposits on the surface, resulting in a poorly cleaned surface. Secondly at high concentrations of alkaline salts, such as in aqueous concentrates in which typically the cleaning compositions are supplied to the end user, these additives are not soluble.
Formulators also use low foam or defoaming nonionic surfactants in these cleaning formulations to minimize foam. Examples include EO/PO block copolymers, branched alcohol ethoxylates, capped alcohol ethoxylates and the like. However, the addition of hydrotropes or hydrotropic co-surfactants that couple the electrolytic component and the low foam/defoam nonionic component together can result in foam stabilization, foam addition or foam boosting negating the effect of the low foaming or defoaming nonionic. This has resulted in many formulators avoiding the use of hydrotropes in their cleaning formulations. Additionally, these cleaning formulations have the lowest foam profile when the cleaning is done at temperatures above the formulations cloud points which results in cleaning solutions that are unstable and inefficient. Also, these formulations tend to have depletion problems especially in enclosed re-circulator systems. This requires that the nonionic surfactant be replenished in order to prevent flash foam occurrence.
The present invention has solved the deficiencies of the prior art by providing low foaming and/or defoaming formulations, which comprise an alkoxylated quaternary ammonium compound and at least one nonionic compound of a specific structure.
The present invention generally relates to low foaming and/or defoaming cleaning formulations which comprise a synergistic combination of one or more hydrotropic alkoxylated quaternary ammonium compounds and at least one nonionic surfactant based on branched alcohols. The nonionic surfactant may be selected from structures having 3 to 12 moles of ethoxylation, but preferably have an average of 3-6 moles of ethoxylation with either narrow or broad range distribution.
The present invention generally relates to low foaming and/or defoaming cleaning formulations which comprise a synergistic combination of one or more hydrotropic alkoxylated quaternary ammonium compounds and at least one nonionic surfactant based on branched alcohols.
The hydrotropic alkoxylated quaternary ammonium compound is preferably selected from the group of compounds represented by General Formula I, below.
R1R2R3R4N+Xxe2x88x92xe2x80x83xe2x80x83(I)
wherein R1 is a linear or branched, saturated or unsaturated C6-C22 alkyl group;
R2 is C1-C6 alkyl group or R1;
R3 and R4 are C2-C4 random or block polyoxyalkylene groups; and
Xxe2x88x92 is an anion, preferably chloride, methyl sulfate, bromide, iodide, acetate, carbonate, and the like.
Preferred compounds within the scope of general Formula I are represented by General Formula II, below. 
wherein R1, R2, and Xxe2x88x92 are as defined above;
each R5 is independently at each occurrence C1-C2 alkyl or H, provided that R5 is a C1-C2 alkyl in at least one occurrence; and
A and B are integers greater than or equal to 1 wherein A+B is 2-50.
Most preferred hydrotropic quaternary ammonium compounds within the scope of the present invention are as shown below where R=linear or branched, saturated or unsaturated C12-C22 alkyl, n+nxe2x80x2=0-10, m+mxe2x80x2=1-20, y+yxe2x80x2=0-20, and Xxe2x88x92 is an anion, preferably chloride or methyl sulfate, provided that when n+nxe2x80x2=0, y+yxe2x80x2 is at least 1. 
An especially preferred hydrotropic quaternary ammonium compound is Berol CHLF available from Akzo Nobel Surface Chemistry LLC, Chicago, Ill., USA: 
where R is tallow alkyl, n+nxe2x80x2=2, m+mxe2x80x2=12, y+yxe2x80x2=5 and X is methyl sulfate.
The quaternary ammonium compound described in this invention may be prepared by quaternization of the starting amino compound described below using known methods such as that described in U.S. Pat. No. 5,885,932 which is incorporated herein by reference. The fourth substituent added to the amino nitrogen by quaternization is preferably a group selected from alkyl, or alkenyl group having 1-4 carbons. Any suitable anion can be employed. Preferred anions include, but are not limited to, a member selected from the group consisting essentially of methyl sulphate, carbonate, chloride, fluoride, bromide, acetate and the like.
The starting amino group can be prepared by reacting an amine selected from the group consisting of R1xe2x80x94NH2 and R1R2NH wherein R1 and R2 as in structure (I); with at least one propylene oxide and at least one alkylene oxide. Preferred alkylene oxides include but are not limited to ethylene oxide, propylene oxide, isobutylene oxide, butylene oxide and mixtures thereof. The compounds of the present invention are made in such a way as to introduce varying numbers of alkylene oxide units onto the amino nitrogen. The additional alkylene oxide groups may be all the same, such as, for example, one or more ethylene oxide units, or the groups may be different to form, for example, block copolymer chains of ethylene oxide and propylene oxide units, random copolymer chains consisting of several units of each of two or more different alkylene oxides, or alternating units of two or more alkylene oxides. Any conceivable combination of alkylene oxide units up to 50 units long may be employed at each available location on the amino nitrogen. For example, the amino nitrogen may contain two different alkylene oxide chains attached thereto or two chains that are the same.
In a preferred embodiment, block copolymer chains of ethylene oxide and one or more of propylene oxide or butylene oxide are employed. Preferably, the molar weight of the compounds used in the present invention is less than 8000 though higher molecular weight compounds can be employed. Typical compounds suitable for use in the present invention include, but are not limited to, bis(hydroxyethyl)methyltallow alkyl, ethoxylated, propoxylated, methyl sulphate; cocobis(2-hydroxyalkyl)methylammonium chloride; polyoxyalkylene (15) cocomethylammonium chloride; oleylbis(2-hydroxyalkyl)methyl ammonium chloride; polyoxyalkylene (15) stearylmethyl ammonium chloride; N,N-bis(2-hydroxyalkyl)-N-methyloctadecanaminium chloride; N-tallowalkyl-N,Nxe2x80x2-dimethyl-N-Nxe2x80x2-polyalkyleneglycol-propylenebis-ammonium-bis methylsulphate; polyoxyalkylene (3) tallow propylenedimonium dimethylsulphate; coconut penta-alkoxy methyl ammonium methyl sulphate; polyoxyalkylene (15) cocomonium methosulphate; isodecylpropyl dihydroxyalkyl methyl ammonium chloride; isotridecylpropyl dihydroxyalkyl methyl ammonium chloride; methyl dihydroxyalkyl isoarachidaloxypropyl ammonium chloride; and mixtures thereof.
The nonionic surfactant employed in the context of the present invention is preferably selected from the group of compounds represented by General Formula III, below
Rxe2x80x94Oxe2x80x94(CH2CH2O)nHxe2x80x83xe2x80x83III
wherein R is a branched alkyl group with 3-12 carbon atoms, preferably a Guerbet alcohol type with 10 carbon atoms or less and/or mixtures thereof, and n=3-12, but preferably 3-6 moles of ethoxylation with either narrow or broad range distribution. Specific examples of nonionic surfactants employable in the context of the present invention include but are not limited to:
polyoxyethylene (3) 2-ethylhexanol, polyethyleneglycol-4 ethylhexyl ether, polyethyleneglycol-5 ethylhexanol, polyoxyethylene (4) 2-ethylheptyl, polyoxyethylene (5) isodecanol and polyoxyethylene (5) 2-propylhepanol.
The formulation of the invention generally contains from about 0.1% to about 12% by weight nonionic surfactant, preferably from about 1% to about 8% and still more preferably from about 2% to about 4%. The present formulation also preferably contains, in combination with said nonionic compound, from about 1% to about 20% by weight alkoxylated quaternary ammonium compound, preferably between 2% to about 10%, and still more preferably between about 4% and about 8%. This synergistic combination of one or more hydrotropic alkoxylated quaternary ammonium compounds and at least one nonionic surfactant based on branched alcohols produces a clear and stable cleaning formulation, with unusual foam collapse properties in the presence of typical cleaning additives such as NaOH, EDTA, TKPP, glycols, corrosion inhibitors, phosphonates, solvents, carbonates, borates, citrates, acids, silicates and the like.
The low foaming/defoaming cleaning compositions of the present invention are ideal for applications that demand low, fast breaking foams to avoid overflow, product loss, pump cavitation, and streaks or films on treated surfaces after drying. Several specialized categories of cleaning which meet this criteria include but are not limited to Cleaning In Place formulations, automatic floor scrubber formulations, automatic dishwasher formulations, re-circulatory metal parts cleaning formulations and the like.
The specialized cleaning formulations of the invention may also be formulated with ingredients know in the art. As nonlimiting examples, such formulations may include hydrotropes or coupling agents, surfactants, thickening agents, chelating agents, builders, defoamers and anti-foam agents, corrosion inhibitors and the like.
Hydrotropes or coupling agents include but are not limited to glycol ethers, alcohols, acrylic polymers, sodium xylene sulphonate, phosphate esters, amphoteric surfactants, alkoxylated carboxylates, aminopropionates, glycerine, alkylpolyglucosides, alkanolamides, quaternary ammonium compounds or mixtures thereof.
Surfactants, include but are not limited to, amphoteric, cationic, nonionic, anionic classes and mixture thereof.
Thickening agents include, but are not limited to, associative polymers and copolymers, acrylic polymers, amides, xanthan gums, cellulosic polymers, modified clays, amine oxides, ethoxylates amines, silica, silicates, polyvinyl pyrrolidone and mixtures thereof.
The electrolytic components can consist of chelating agents or builders. Chelating agents include but are not limited to gluconates, citric acid, sodium ethylenediaminetetraacetic acid, phosphonates, phosphoric acids, phosphates, polyphosphates, nitrotriacetic acid, ethylenediaminebis(2-hydroxyphenylacetic acid) and mixtures thereof. Builders include, but are not limited to soda ash, acrylic polymers, silicates, phophonates, phosphates, carbonates, citrates, sodium hydroxide, potassium hydroxide, triethanolamine and mixture thereof.
Corrosion inhibitors include but are not limited to alkanolamides, aliphatic carboxylic acids, amides, amines, diamines, polyamines, phosphoric acid, borates, oxazolines, phosphate esters, benzotriazole, azoles, imidazolines, amphoteric surfactants, silicates, phophonates, gluconates, fatty acids, thioazoles and mixtures thereof.
Other optional components may be included in the formulations of the present invention. These include but are not limited to liquid carriers such as water, pH modifiers, enzymes, bleaching agents, bleach activators, optical brighteners, soil release agents, antistatic agents, lubricants, preservatives, perfumes, colorants, anti-redeposition agents, dispersing agents, acidifying agents and solvents.